Method of coating metals.



No. 881,029. PATENTED MAR. 3, 1908.

A. SANG.

METHOD OF COATING METALS. APPLICATION nun APB.13. 1901.

ALFRED SANG, OF SEWICKLEY, PENNSYLVANIA.

METHOD OF COATING METALS.

7 Specification of Letters Patent.

Patented March 3, 1908.

Application April 13, 1907. Serial no. 367,916.

To all whom it may concern:

Be it known that I, ALFRED, SANG, of Sewickley, Allegheny county,Pennsylvania, have invented a new and useful Method of Coating Metals,of which the following is a full, clear, and exact description,reference being had to the accompanying ,drawing,

forming part of this specification, in which though other materials maybe used, which is then covered and sealed. ,This coating box or recetacle is connected by a pipe or conduit wit a retort or ot contaimng thedust of the coating meta. In the case of zinc, this dust will referablybe the ordinary commerical zinc list which contains some oxid of zinc.If the metal dust does not contain oxid, such oxid should be added toit. I also preferably employ a reducing or fixing agent, such as cyanldof potassium, asphaltum, coal oil, or other reducing agent or agentswhich may be placed in the retort, in

the coating box, or applied as a coating on the articles in the box. Theproportion of the reducing agent may be varied widely Without materiallyaffecting the result. The pot or retort containing the zinc dust is theneated to a point below the melting point,

-but sufiicient to vaporize this zinc dust.

The temperature is preferably fromv two hundred to five hundred degreescentigrade, though this may be- .varied Within certain limits, dependingupon the vaporization oint of the particular metal dust employed.

. he coating receptacle is also preferably heated in orderto prevent thedeposition of w the coating metal upon its inner surface, and

/ Lgrade.

this temperature imay be varied Widely, "though I prefer to heat the boxfrom about two'hundred to-three hundred degrees centi In the form ofapparatus shown in the drawings, 2 is the retort containing the metalcontaining the metal articles 4, and 5 is the pipe connecting the boxesin which I preferablyrovide a central valve 5. I have shown t e retortas mounted in a setting connected to an external combustion chamber 6,the gases passing from ,the setting through a flue 7 containing thecoating receptacle on their Way to the stack flue.

8 and 9 represent the removable covers of the retort and coating boxrespectively, these preferably having flanges seating in roovescontaining asbestos gaskets, or simiar packing material,

When the dust in the retort is heated to the vaporizing point, the vaporfrom the dust passes into the coating receptacle, reacts coating metalupon the articles. This coating is of atough, strongly adherentcharacter, and under most conditions is of a fine granular nature andbright, or else crystallinein character. It is substantially amalgamatedor alloyed with the surface portionof the article itself. A i i Thedepth or thickness of the coating or deposit may be varied, according tothe length of time which the operation is continued, the temperatureemployed, &c. Pyrometers 10 and 11 are preferably employed for the potor retort,-and also the coating receptacle,' so that the heat may bekept withm desirable limits.

Instead of supplying the reducing agent in the retort or pot with themetal dust, it may beapplied to the articles in the coating receptacle.'In such case ilhave found that where asphaltum is used as a reducingagent forming'a coating on the article, the zinc or other metallicdeposit will be formed under the asphaltum. This is of especialadvantage in. structural steel, since the structural shape will not onlybe providedwith the protective metallic coating, but this coating inturn covered by the asphaltum, without any further operation. Articlesprovided with a coveringof paint or non-metallic materials may thus beprovided with a metallic coating under'the non-metalliccovering, usingthe reducing agent ineither receptacle, or as the non-metallic coatingitself. I have found that whereeither asphaltum,

dust and reducing agent, 3 the coating box bitumen, heavy oil or similarmaterial is used (ill with the reducing agent and deposits the with themetal dust, a double coating is given, the inner coating being metallicand. the outer one non-metallic.

The advantages of my invention will be apparent to those skilled in theart. The articles do not need to be brought into contact with. the metaldust, and large and heavy articles may be treated cheaply and easily.The coating is of the highly desirable tou h adherent character. Theprocess may )e carried out by placing the articles in the same pot orreceptacle with the dust, and without contact therewith; metal dustother than zinc may be employed; and many.

other changes may be made without departing from my invention.

I claim 1. The process of depositing coating metal upon a metallicsurface, consisting in vaporizing the dust of the coating metal, andsubjecting the metal surface to be coated to the action of said vaporwhileout of contact with the dust; substantially as described.

2. The method of'coating metal surfaces, consisting in heating andvaporizing the dust of the coating metal, treating the vapor with areducing agent, and depositing the vapor upon the surface to be coatedwhile said surface is out of contact with the metal dust; substantiallyas described.

The method of coating metal surfaces, consisting in vaporizingthe dustof the coating metal in the presence of a reducing agent, heating thesurface to be coated, and subjecting it to the action of said vaporwhile out of contact with the dust; substantially as described.

4. The process of depositing coating metal upon a metallic surface,consisting in vaporizing the dust of the coating metal by applying heatof a temperature below the va oriz ing temperature of the metal itself,an subjecting the metal surface tobe coated to the 6. The process ofdouble coating a metallic surface, consisting in vaporizing the dust ofthe coatin metal, and subjecting the metal surface to be coated to theaction of said vapor while out of contact With the dust and in thepresence of the vapor of a non-metallic materlal, which acts as areducing agent for coating; substantially as described.

In testimony whereof, I have hereunto set my hrnd. ALFRED SANG.Witnesses:

JonN MILLER, H. M. CORWIN.

the metallic vapor and gives an additional

